Indexing and feeding systems for apparatus for gelatin coating tablets

ABSTRACT

An apparatus for controlling the loading and feeding of tablets onto carrier plates for transfer to various processing stations of a coating system includes a novel plate indexing apparatus having a box cam follower device mounted to an engagement bar for incrementally advancing the plates in a precisely controlled manner. A second complementary shaped engagement bar provides a locking mechanism to ensure the plates are always under positive control. In one embodiment the plate indexing apparatus also controls the feeding of the tablets. An alternative embodiment includes a vacuum pick-up system for feeding tablets onto the carrier plates as the plates are incrementally advanced.

This is a division of application Ser. No. 08/387,973, filed Feb. 10,1995, now U.S. Pat. No. 5,538,125 which is a continuation of applicationSer. No. 08/003,334, filed Jan. 12, 1993, abandoned, which iscontinuation-in-part of application Ser. No. 07/609,482, filed Nov. 5,1990, now U.S. Pat. No. 5,228,916, all of which are hereby incorporatedby reference.

The present invention relates to methods and apparatus for forming acoating on a product and, more particularly, to methods and apparatusfor forming a coating comprised of a gelatinous substance on a tablet.The present invention further relates to methods and apparatus forloading tablets into the coating apparatus for processing.

The present invention is related to my prior patents U.S. Pat. Nos.4,921,108 issued on May 1, 1990; 4,867,983 issued on Sep. 19, 1989;4,820,524 issued on Apr. 11, 1989 and 4,966,771 issued on Oct. 30, 1990,and my U.S. patent application Ser. No. 483,154, filed Feb. 22, 1990,now U.S. Pat. No. 5,234,099, which are assigned to the assignee of thepresent application and incorporated by reference as if fully set forthherein.

The present invention is also related to my U.S. patent application Ser.Nos. 08/003,158, now U.S. Pat. No. 5,503,673 issued Apr. 21, 1996,08/003,347, now U.S. Pat. No. 5,466,250 issued Nov. 14, 1995,08/003,348, now U.S. Pat. No. 5,436,026 issued Jul. 25, 1995 and08/003,349, now U.S. Pat. No. 5,498,411 issued Mar. 12, 1996 all filedconcurrently herewith, which are all assigned to the assignee of thepresent application and incorporated by reference as if fully set forthherein.

BACKGROUND OF THE INVENTION

Many products, from prescription drugs to commonly available vitamintablets to candy, are manufactured in a form which may be described as a"tablet." The primary function of a tablet is to provide a single doseor "serving" of the product in a manner which is convenient tomanufacture, package and consume. As pointed out in my previous patentsand applications, referenced above, it has been found that certainindividuals suffer from physiological and psychological problems whichimpede their ability to swallow tablets. It has also been found that byproviding tablets with a smooth coating, such as a coating comprised ofgelatin or a gelatinous substance that the "swallowability" of a tabletis greatly enhanced. Such coatings and the general considerationsinvolved in their application, such as preparation and drying time, arewell known to those of ordinary skill.

In addition to enhanced swallowability, there are numerous other reasonsthat it is desirable to provide a coating on a tablet. Such coatingsprotect the underlying product from deterioration and also serve topermit identifying colors or markings to be incorporated onto the designof the product, promoting product differentiation and brandidentification. As pointed out in my previous patents and applications,it is also desirable in some instances to overlap two or more coatingsto form a seam, thereby simulating the appearance of a hard gelatincapsule while providing a coated, solid (and thus tamper resistant)product.

Methods and apparatus for applying a gelatinous coating or other coatingto a product which is in the form of a tablet are well known to those ofordinary skill. Such methods may include pan dipping or vacuum sprayingof the coating material on to the tablet. Such methods are crude,however, producing uneven coatings which are generally unacceptable forcommercial use. In an effort to improve the state of the art, theinventions disclosed by my previous patents and applications haveprovided methods and apparatus whereby individual products are heldpartially within a sleeve or "collet" and the exposed portion of theproduct precisely lowered into a dipping tank. As disclosed, bars orplates containing a plurality of product to be dipped are conveyed androtated and the product itself is manipulated to provide even coatingsof high quality and consistency at high volume. These inventions,however, do not permit every type of product such as certain styles oftablets and medicaments to be coated--or at least to be coated in aparticular manner. For example, dipping the circular face of asubstantially cylindrical tablet whose height is relatively smallcompared to its diameter would be difficult using the apparatusdisclosed by my prior patents and applications, particularly if acircumferential seam is desired. Other examples include the difficultyof coating either a fragile product or applying fragile coatingcompositions. It has been found that certain coatings will be marred bythe friction fit within the collets or similar retaining devices makingthese unsuitable for use in the apparatus of my prior inventions.

It is known to transport individual tablets or capsules through animmersion coating bath by retaining the tablets on individual vacuumtubes. For example, U.S. Pat. No. 3,896,762--Banker discloses a rotarycoating apparatus for pharmaceutical solid dosage forms. Since thesurface of the coating is horizontal it is tangential to the path of thetablet; accordingly, Banker discloses that it is necessary to rotate thevacuum tube holding the tablet around its longitudinal axis to achievean even coating. There are, however, a number of practical shortcomingsin the apparatus disclosed. First, although a dryer and ejector aredisclosed, the overall system does not lend itself to high volumeproduction or provide for modifications in drying time or inspection,etc. Secondly, the system disclosed by Banker is directed to passingone-half or more of the total depth dimension of the tablet through thecoating solution. The tablet is then randomly ejected, with no provisionbeing made to align or otherwise control the orientation of the tabletand the uncoated portion, if any, which exists. Moreover, there is noprovision for adjusting the coating to achieve multi-colored orcapsule-like coated products. Therefore, one of ordinary skill willappreciate that the system disclosed by Banker is of limited use incurrent manufacturing environments, where high volume and flexibilityare important, along with the need for consistency and high quality.

Therefore, there exists a need for methods and apparatus which canconsistently place a precisely defined amount of coating material on anindividual product. Such methods and apparatus should be capable ofproducing coated products at high volume and should possess inherentflexibility to permit new designs and types of coatings to beincorporated without an undue degree of retooling. Moreover, it isextremely important that the products be introduced into the system in ahighly controlled manner to enable the coatings to be accuratelyapplied.

SUMMARY OF THE INVENTION

The present invention provides novel product loading apparatus andmethods for precisely controlling the insertion of solid tabletmedicaments onto carrier plates for transfer to various processingstations for coating the tablets with gelatin. The invention includes anindexing means for incrementally advancing a plurality of productcarrier plates through a feeder device. The plate indexing means alsoincludes means for ensuring that the carrier plates are always underpositive control throughout the advancement procedure. In one embodimenta box cam mechanism moves a first plate engagement bar in fourdirections to advance the carrier plates and a two-way cam mechanismmoves a second plate engagement bar in two directions to alternatelylock and unlock the plates. The plate indexing means is connected to thefeeder device in order to coordinate the loading of tablets onto holdersin the carrier plates in cooperation with the advancement of the plates.A setting pin is connected to the plate indexing means to properly seatthe loaded tablets in their individual holders prior to advancing toother processing stations. In one embodiment, a passive loadingmechanism is described in which tablets are loaded onto the holders bythe movement of the carrier plates. In another embodiment, the tabletsare loaded using a rotatable vacuum pick-up head system for picking uptablets from the feeder device and placing them onto the productholders. The feeder device is also provided with selection means forsifting out partial tablet pieces. The precise indexing of the productcarrier plates and the loading and setting of the tablets onto theplates in accordance with the present invention greatly increases theefficiency of the gelatin coating processing system resulting in greaterproductivity and lower costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially diagrammatic, partially schematic representationof the coating apparatus of the present invention.

FIG. 2 is a broken away, partially cross-sectioned side view of aportion of the apparatus of FIG. 1.

FIG. 3 depicts a cross-sectional view of the tablet holders and plateused in one embodiment of the present invention.

FIG. 4 is a broken away cross-sectional view of the plate of FIG. 3,illustrating the tablet holder and vacuum tube used in one embodiment ofthe present invention.

FIG. 5 is a partially diagrammatic, partially schematic representationof the steps of a preferred method for coating a tablet in accordancewith the present invention.

FIG. 6 is a broken away cross-sectional view of a portion of anotherembodiment of the present invention in which a band of coating materialis applied to the products.

FIGS. 7a and 7b are cross-sectional views of another embodiment of atablet holder of the present invention.

FIG. 8 is a plan view of a product carrier plate of one embodiment ofthe present invention.

FIG. 9 is a partial elevational view of the plate indexing means of thepresent invention.

FIG. 9a is a cross-sectional view taken along lines 9--9 of FIG. 9.

FIG. 10 is a cross-sectional view taken along lines 10--10 of FIG. 9.

FIGS. 11a-11e are a schematic representation of the sequential movementof the engagement bars of the indexing means of FIG. 9.

FIG. 12 is a diagrammatic representation of the feeder means of thepresent invention.

FIG. 13 is a diagrammatic representation of a perforated plate of aseparation means of one embodiment of the feeder means of the presentinvention.

FIGS. 14a and 14b are cross-sectional views of the passive means fordispensing tablets onto a product holder.

FIG. 15 is a cross-sectional view of the setting means of the presentinvention.

FIG. 16 is a cross-sectional view of one embodiment of a vacuum pick-updevice of the product dispensing means of the present invention.

FIG. 17 is a cross-sectional view of another embodiment of thedispensing means of FIG. 16 with a setting means attached thereto.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A generalized representation of the apparatus used in a preferredembodiment of the present invention is shown in FIG. 1. It will beunderstood that the descriptions set forth may be applied to numeroustypes and shapes of products. The type of tablet illustrated and thesequence shown are for purposes of explanation only.

A plurality of the product 10 to be coated is placed in a feeder means80. Preferably, the feeder will be comprised of a hopper 82 and a seriesof feeder tubes 84 which align, orient and dispense the product 10 inthe appropriate manner. Initially disposed directly beneath the feedertubes 84 and in registration therewith is a plate 50. The plate 50 has aplurality of tablet holders 30 which, as explained below, restrain theproduct during certain portions of the coating process. The tabletholders 30 preferably correspond to the feeder tubes 84 and thus, mostpreferably, each tube 84 feeds a single product 10 into a single tabletholder 30.

Conveyor means transfer the plate 50 from the feeder 80 to the vacuumchamber 60. In a preferred embodiment shown in FIG. 1, the vacuumchamber 60 is adapted to receive and make vacuum tight connections withtwo plates 50. As shown by the arrows, the vacuum chamber 60 is furtherprovided with manipulating means whereby it may be moved up and down,and rotated about a pivot point 62.

A first dipping tank 120 is disposed beneath the vacuum chamber 60 andis filled with a quantity of coating material. Preferably a coatingmaterial such as gelatin is used and, most preferably, the dipping tank120 is provided with pumps and conduits whereby the coating material iscontinuously circulated. As illustrated, the dipping tank is mostpreferably constructed to form a meniscus surface 122 by pumping thecoating material into an inner tank 124 which is permitted to overflowinto the larger tank 120. Such a system prevents the coating materialfrom hardening while the apparatus is in use and helps to ensure thatthe coating material presents the same even and substantially levelsurface to the product being dipped at all times.

In operation, the plate 50 is moved into engagement with the vacuumchamber 60 and then the chamber 60 and the plate 50 are rotated one-halfrevolution. As explained below, the vacuum chamber 60 creates a vacuumwithin the tablet holders 30 which holds the product 10 in place and inthe correct orientation to be dipped. The vacuum chamber 60 is nextlowered into dip tank 120 to a predetermined depth and then withdrawn.The vacuum chamber 60 is then rotated one and one-half revolutions inorder to return the plate 50 to its original orientation. The additionalfull revolution beyond that required provides a dwell time, permittingthe coating to initially "set" and also prevents the coating fromrunning or sagging due to gravity by constantly reorienting the product10. However, a rotation of as little as one-half of a revolution may beadequate in some instances. At this point, the plate 50 may be returnedto the conveyor means and removed from the vacuum chamber 60.

The design of the vacuum chamber 60 and placement of the dip tank 120illustrated permit a wide variety of coatings to be effectively andefficiently achieved. Although the dipping of a substantiallycylindrical tablet having concave faces to form a coating havingcircumferential seam is illustrated, those of ordinary skill willunderstand that numerous other shapes of product, as well as othercoating schemes are possible using the apparatus disclosed. As will beexplained below, the shape of the tablet holders 30 and the design ofthe sub-components of the vacuum chamber 60 may be readily adapted forparticular requirements. Also, as illustrated in FIG. 1, throughput maybe increased by designing the vacuum chamber 60 to form a vacuum tightseal with further plates 50, such that each time the vacuum chamber 60is rotated, a plate 50 which has already been lowered into the dippingtank 120 is returned to the conveyor means.

After the plate 50 containing the partially coated product 10 is removedfrom the vacuum chamber 60 the plate may be passed through a dryer means130 for curing the coating material. As will be understood by those ofordinary skill, the dryer 130 will be chosen to correspond to the heatand moisture requirements of the coating material being used. Radiantheat, forced hot air, microwave dryers and combinations of these typesare among the types available. Depending upon the type of dryer 130chosen, one or more conveyors and other apparatus may be required totransfer the plates 50 into and out of the dryer 130.

After the coating has been cured, the plate 50 is again returned toconveyor means and is preferably transferred to another location. Atthis point, although only a portion of each individual product 10 hasbeen coated, it may be desirable to eject the product 10 and considerthe process complete. This may be true, for example, where the producthas already been coated and the above-described process is carried outto add a second color to a portion of the product.

In a preferred embodiment, however, the present invention providesmethods and apparatus which permit the uncoated portion of the product10 to be coated. First, a second plate 50' is positioned in registrationwith the product contained on the first plate 50, as illustrated inFIG. 1. The second plate 50' is lowered until the coated side of theproduct 10 is disposed within the tablet holders 30' of the second plate50'. The resulting "sandwich" of the first plate 50, the product 10 andthe second plate 50' is then rotated one-half revolution by theconveyor/manipulator means. As shown, the positions of the plates 50,50'are thus reversed, and when the first plate 50 is removed the uncoatedportion of the product 10 is exposed. The second plate 50' may then betransferred to the starting point of the dipping process and put throughthe sequence of manipulations necessary to form a coating which were setforth above using either the same apparatus or further apparatus, usingeither the same coating material or a different coating material.

In the instance where the same apparatus is used to place coating uponthe uncoated portion of the product 10, the second plate 50' may bepreferably conveyed or otherwise transported to a location just beforethe vacuum chamber 60, i.e., between the vacuum chamber 60 and thefeeder 80 illustrated in FIG. 1. The second. plate 50' would simply beinserted into engagement with the vacuum chamber 60 and the abovedescribed apparatus would carry out substantially the same sequence offunctions in terms of dipping the product 10, curing the coating asneeded, etc. After the product 10 has been fully coated and cured, itmay be ejected prior to the transfer stage between the first and secondplates 50,50'.

In another embodiment of the present invention, after the partiallycoated product has been transferred to the second plate 50', the plate50' may enter a duplicate series of apparatus, such as that describedabove with reference to FIG. 1. In other words, a second vacuum chamber,dipping tank, dryer, and manipulating and conveying apparatus may beprovided. After the product 10 is coated and cured using this second setof apparatus, the completed product is ejected.

Referring now to FIG. 2, a more detailed view of the vacuum chamber 60described above is shown. As explained above, in a preferred embodimenttwo plates 50 (or 50') are retained in a vacuum tight seal upon thevacuum chamber 60, thereby permitting more efficient indexing betweenthe raising and lowering of the apparatus and the infeed and outfeed ofthe plates 50 from the vacuum chamber 60.

As shown, the entire chamber may be raised or lowered to bring theproduct 10 into contact with the surface of the coating material 122.The vertical motion also preferably provides a transfer between thevacuum chamber 60 and the conveyor means, as shown in phantom in FIG. 2.This latter vertical movement also provides clearance when the vacuumchamber 60 is rotated during the dipping process explained above withreference to FIG. 1.

Further details of the vacuum chamber 60 are shown in FIG. 3, whichillustrates broken-away section of the plate 50 and the vacuum chamber60. As seen in cross-section, the plate 50 has a plurality of tabletholders 30 inserted into a series of openings. The plate 50 rests uponthe vacuum chamber 60 and forms a seal therewith. A plurality of vacuumtubes 100 extend through the tablet holders 30 and, when in use, engageand slightly lift the product 10 from the tablet holders 30 as shown.The vacuum created within the vacuum chamber 60 is channeled through thevacuum tubes 100 by a manifold or similar means, thereby permitting thevacuum to act upon the surface of the product 10 when contacted by thevacuum tubes 100. By providing vacuum tube actuator means 102 forraising and lowering the vacuum tubes 100 relative to the vacuum chamber60, the vacuum tubes may be selectively placed in the raised positionillustrated. The actuator 102 may be a common bar or mounting structurewhich is moved by a gear, cam or pulley system.

When in the position illustrated, it is possible to invert or otherwisemanipulate the product 10 as described above without friction or the useor mechanically actuated clamps. The vacuum handling system disclosed bythe present invention provides a secure retention of the product whileminimizing the possibility of damaging either the coating or the product10 itself. As explained above, the methods and apparatus of the presentinvention are useful for numerous shapes and sizes of product 10,however, most preferably, the product 10 will have one or more curvedsurfaces, as illustrated. The curved surfaces permit the tubes 100 to bemade from a rigid material such as stainless steel. Those of ordinaryskill will realize however, that nearly any shape and any orientation ofproduct may be retained using appropriately designed vacuum tubes.Finally, in certain instances it will be desirable to provide a cushionor resilient tip on the distal end of the vacuum tube in order to ensurea sufficient grip.

Referring now to FIG. 4, one embodiment of the tablet holder 30 isillustrated. A shoulder 32 is formed at a first end of the tablet holderto provide a positive stop. A groove is formed at a second end, intowhich an "O" ring or the like may be engaged to retain the tablet holder30 in the plate 50. As will be understood by those of ordinary skill,the tablet holder 30 and the plate 50 may be in certain instances formedas an integral component. FIG. 4 also illustrates the vacuum tube 100 inthe withdrawn position. When the vacuum tube 100 is in the withdrawnposition, the depression formed in the tablet holder 30 is the onlymeans for restraining the product 10 (not shown in FIG. 4).

FIGS. 7a and 7b show a second embodiment of the tablet holder for use inplates 50. Tablet holder 31 shown in FIGS. 7a and 7b is provided with aplurality of slots 33 forming resilient fingers 35. FIG. 7a is across-section taken through the slots 33, and FIG. 7b is a cross-sectiontaken with the holder 31 rotated 90° from its position in FIG. 7a. Inthe embodiment shown in FIGS. 7a and 7b, a pair of slots 33 are providedthereby forming a pair of resilient fingers 35. Slots 33 are disposedlongitudinally through the walls of holder 31. Holder 31 is generally inthe form of a cylinder having a central bore 37. Tablet holder 31 isretained in the opening 39 of plate 50 by shoulder portion 41 on one endand angled flange 43 on a second end. For ease in installation the sizeof upper surface 45 of angled flange 43 may be significantly reduced atthe portion of the side walls located immediately adjacent to slots 33as shown in FIG. 7a. The flange 43 may gradually increase to its largestsurface area located 90° from slots 33 as shown in FIG. 7b. The holder31 is also provided with seat 47 for accepting a tablet therein. It willbe understood by those of ordinary skill that the seat 45 may be shapedappropriately to match the shape of the product being held.

The holder 31 is a "push-in" holder that does not require o-rings or thelike that are susceptible to wear and tear. In order for the holder 31to be secured in the plate 50, the outer diameter of the annularresilient fingers 35 forming the cylinder of holder 31 must be slightlylarger than the diameter of the opening 39 in plate 50. The angle offlange 43 enables the holder 31 to be inserted through the opening 39and to cause the fingers 35 to be slightly compressed toward each otheras the holder is passed through the plate 50. When the flange 43 clearsthe opening 39 and plate 50, the resilient fingers 35 spring back totheir original position causing flange 43 to engage plate 50 therebysecuring the holder 31 therein.

FIG. 8 shows a plan view of a carrier plate 50 for retaining theplurality of product holders 30 or 31. The carrier plate 50 of FIG. 8includes a plurality of longitudinal rows of individual product holders31. The plates 50 are preferably from 4 to 5 inches wide andapproximately one-half to one inch thick. In one embodiment, the plate50 is made about 23 to 24 inches in length enabling the plate to include7 rows each containing 33 holders for a total of 231 holders.

A preferred embodiment of the carrier plate 50 of the present inventionis machined from tool plate aluminum. It is also preferred that thealuminum have a protective coating such as an anodized coating appliedto the surface. The plate 50 is rectangular and symmetrical, having foureasily spaced slots 51 disposed near the four corners which engage theconveyor and/or holding means. Also provided at either end are alignmentand transport holes 52 which contain retaining bushings 53 which areused to manipulate the plate 50 as it is advanced through the feedermeans 80 and through other processing stations.

The present invention also provides methods for coating a product 10 inaccordance with the present invention. A preferred embodiment of themethods of the present invention is illustrated by the sequence of viewsin FIG. 5. For purposes of illustration and explanation a single product10, vacuum tube 100 and tablet holder 30 are illustrated, along withbroken away portions of other apparatus such as the plate 50. As shownin the upper left section of FIG. 1, a plate 50 containing a tabletholder 30 is positioned beneath the feeder means 80 for feeding a tabletdescribed above and a product 10 is disposed within the tablet holder30. Next, the plate 50 containing the individual products 10 is movedinto the vicinity of the vacuum chamber 60, where it is cleaned of dustand particulate matter. For clarity, the representation of the vacuumchamber 60 is omitted from the other views shown in FIG. 5. Anindividual vacuum tube 100 is then brought into position and placed inclose proximity or contact with the product 10. At this point, thevacuum created within the vacuum tube 100 "picks up" or engages theproduct 10. After the individual products 10 have been engaged by thevacuum tubes 100, the entire plate 50 is rotated one-half of arevolution, suspending the product 10 by the vacuum tube 100. The vacuumtube 100 and the product 10 attached thereto may now be moved intoposition and lowered into a coating tank 120. The depth to which theproduct 10 is lowered is a function of the motion of the vacuum tubes100 and plate 50, which may be precisely regulated by hydraulicactuators, gear trains or other means for actuating the vacuum tube 100and/or moving the plate 50. The vacuum tube 100 and the partially coatedproduct 10 are then withdrawn from the coating tank 120, but the product10 is not fully withdrawn into its holder 30. Instead, the plate 50 andpartially extended vacuum tubes 100 are rotated one and one-halfrevolutions, returning the plate 50 to its initial orientation. Theadditional revolution provides a dwell, permitting the coating toinitially set, as well as aiding in the provided evenness of the coatingby preventing the coating from running due to gravity. In certainembodiments, however, this dwell may be unnecessary and the plate needonly be rotated one-half of a revolution. After the plate 50 has beenreturned to its initial position, the vacuum tube 100 may be withdrawnuntil the product 10 again rests in a holder 30 within the plate 50.Once the vacuum tube 100 has been sufficiently withdrawn, the vacuumconnection to the product 10 is broken and gravity and the holder 30restrain the product 10.

As shown at the lower left portion of FIG. 5, once the individualproducts 10 have been released from the effect of the vacuum, the plate50 bearing the partially coated individual products 10 may be moved intoa dryer 130. Using conveyors or other conventional means, the plates arepushed into the dryer 130 and dried. After the coating has cured and theplates 50 have exited the dryer 130, a second plate 50' is moved intoposition such that the tablet holders 30' in the second plate 50' are inregistry with the tablet holders 30 in the first plate 50, which containthe partially coated product 10. The second plate 50' is lowered towardthe first plate 50 until the tablet holders 30' in the second plate 50'have engaged the product held in the first plate 50. Thus, asillustrated, the product 10 is "sandwiched" between the first and secondplates 50,50'. The pair of plates 50,50' are then rotated one-halfrevolution, thereby reversing the relative positions of the first andsecond plates 50,50'. The first plate 50 is then raised, leaving theuncoated portion of the product 10 on the top, exposed, and the coatedside on the bottom, i.e., within the tablet holder 30 of the plate 50'.

At this point, the preferred embodiment of the method illustrated hascompletely coated and cured a coating on about one-half of the product10. It will be understood, however, that the above-described method maybe repeated by transferring the plate 50' shown in the lower rightsection of the illustration to the upper left section, in other words,to the beginning of the process at the point immediately after theindividual products 10 have been loaded into the plates 50. In thisembodiment of the present invention, the above-described process isrepeated and the remainder of the product 10 is coated. It should befurther understood, however, that in any event, more or less thanone-half of the tablet may be coated to provide different overallcoating effects. For instance, if both "passes" coated less thanone-half the height of the tablet, a band of uncoated product wouldremain exposed. On the other hand, if one or both of the "passes" werecarried out to a depth substantially greater than one-half the height ofthe tablet, an overlapped "seam" appearance would be created.

Referring now to FIG. 6, another feature of certain embodiments of thepresent invention is illustrated. In these embodiments, the vacuum tube100 will be constructed such that it may be rotated about itslongitudinal axis as shown by arrow a in FIG. 6. As understood by thoseof ordinary skill, such rotation may be accomplished using gear trains,belts and pulleys or other means for transferring rotational motion to ashaft. While rotating, the vacuum tube 100 is also acted upon by asource of vacuum, either the vacuum chamber 60 discussed above, oranother source. The product 10 is thus firmly held in place upon therotating vacuum tube 100 as shown. While the product 10 is rotating, itis brought into contact with a rotating wheel 210 or other applicationmeans for applying a coating. Preferably, the rotating wheel 210provided is shaped and manipulated so as to come into close proximitywith a portion of the product 10, such as the central "edge" shown. Asthe wheel 210 and product 10 rotate, the wheel 210 also passes through aquantity of coating material 222 and precisely coats a portion of theproduct 10. The wheel 210 rotates about a shaft 202 in the directionshown by arrow b and is mounted on a support structure 200 at anappropriate angle.

The present invention therefore also discloses methods whereby arelatively narrow stripe or band of coating material may be applied to aproduct. Most preferably, the product and the means for applying thecoating rotate and are placed in close proximity. The means for applyingthe coating is preferably at least partially immersed in a quantity ofcoating material and passes therethrough while rotating. Using theembodiments illustrated in FIG. 6, it is possible not only to provide adifferent color "band" or stripe, but to also increase the thickness ofthe coating in a specified section, thereby creating the appearance of aseam or an overlapped gelatin capsule.

Referring now to FIG. 9, a novel plate indexing means 300 forincrementally advancing a plurality of product carrier plates 50 throughfeeder means 80 of the tablet processing system of the present inventioncan be described. The plate indexing means 300 includes a firstengagement means 302 for engaging one or more of the product carrierplates 50 and a first cam means 304 for providing motion in at least twodirections to the first engagement means 302. In one direction ofmovement the first cam means moves the first engagement means 302 from afirst position to a second position which thereby advances the productcarrier plate 50 an incremental predetermined distance. In the seconddirection of movement, the first cam means 304 returns the firstengagement means 302 to the first position. The first engagement means302 engages the product carrier plate 50 while moving from the firstposition to the second position. The plate indexing means 300incrementally advances the product carrier plates 50 through the feedermeans, partially shown at 80, where tablets 10 are dispensed onto theindividual holders in the plates 50. In a preferred embodiment of thefirst cam means, motion in four orthogonal directions to the firstengagement means is provided. In this preferred embodiment, the firstengagement means is moved into third and fourth positions, out ofengagement with the carrier plates 50, for returning the firstengagement means from the second position to the first position.

In a preferred embodiment of the plate indexing means 300, a secondengagement means 306 is provided for engaging one or more of the platemeans 50. The second engagement means 306 is moved between a firstposition engaging the plate means 50 and a second position out ofengagement with the plate means 50. The second engagement means 306engages the plate means 50 to prevent advancement of the plates 50during the time when the first engagement means is being returned fromits first position to its second position. During this time, the carrierplates 50 must be maintained in position so that the first engagementmeans will be able to re-engage the plates when it is returned to thefirst position. Any movement of the plates during the return may resultin the plates being unable to be re-engaged causing a shut down of thesystem. The second engagement means 306 is moved into its secondposition out of contact with the plates to allow for the controlledadvancement of the plates by the first engagement means 302.

Engagement means 302 is comprised of an engagement bar 310 that extendslongitudinally over the width of a plurality of plates 50. In theillustrative embodiment shown in FIG. 9, the engagement bar 310 extendsover a part or all of six plates. Secured to a bottom surface ofengagement bar 310 are a plurality of engagement pins 312. The pins 312are adapted to fit snuggly into retaining bushings 53 of carrier plates50. Mounted onto an upper surface of engagement bar 310 is cam means304. As shown in FIG. 9, cam means 304 is a box cam comprised of a camfollower 314 and a pair of cams 316 positioned in a pair of cam openings318. As will be more fully explained below, the preferred embodiment ofcam means 304 shown in FIG. 9 provides movement to engagement bar 302 infour orthogonal directions in the same plane thereby creating a "box"motion. This "box" motion causes, for every 360° of motion of cams 316,engagement pins 312 to incrementally move from a first position, throughsecond, third and fourth positions, and back to the first position. The"box" motion is provided by the shape of the cams 316 and openings 318.As can be seen in FIG. 9, openings 318 are generally in the shape of asquare. Each 90° of motion of cam 316 will cause the cain follower andhence the engagement bar to move in one of the four orthogonaldirections. A full 360° of motion therefore provides movement in allfour orthogonal directions.

Engagement means 306 is similar to engagement means 302 and thereforecomprises an engagement bar 320 having engagement pins 322 secured to abottom surface thereof. Cam means 308 is mounted to engagement bar 320and is comprised of a cam follower 324 having a pair of cams 326positioned in a pair of cam openings 328. In the preferred embodimentshown in FIG. 9, the cams 326 and openings 328 are designed to provideonly two directions of motion in the same plane to engagement bar 320.The openings 328 are rectangular in shape as opposed to the square shapeof the cam openings 318. In the illustrative embodiment of FIG. 9, thevertical dimension of openings 318 and 328 are identical while thehorizontal dimensions of 328 are longer than the horizontal dimensionsof openings 318. The size and shape of cams 316 and 326 are identical.However, 180° of motion of cams 326 is required to effect movement toengagement bar 320. For each 180° of motion of cams 326 only one of twodirections of motion along the vertical plane will be provided toengagement bar 320. Engagement bar 320 will hence be moved from theposition shown in FIG. 9 where the pins 322 are out of engagement withplates 50 and to a second position in which the pins 322 are inengagement with plates 50. while in engagement with plates 50,engagement bar 320 prevents movement of the carrier plates 50 andthereby acts as a locking mechanism. Cam follower 324 also includesopening 330 for receiving a positioning bar 331 shown in FIG. 9a that,together with locking wheels 333, prevents movement of engagement bar320 in the horizontal direction. The wheels 333 are mounted to shafts337 and rotate with the shafts 337 and move up and down with camfollower 324. As indicated above, the apparatus of the present inventionis intended to facilitate coating large numbers of tablets. In theembodiment described above, plates 50 are comprised of seven rows of 33tablet holders. Thus, the feeder means must be able to dispense a singlerow of 33 tablets simultaneously onto the carrier plates. It isnecessary, therefore, that the plate indexing means ensure that each rowof 33 tablet holders is advanced to be in proper registration with thefeeder tubes so that all the tablets in the row will be properly seatedin the holders. In a preferred embodiment of the present invention, apair of plate indexing means 300 is provided one on each side of plate50. As shown in FIG. 8, plates 50 include a row of engagement bushings53 on each transverse side in order to accomodate engagement pins oneach side. A single pair of drive shafts that extends through the cams316 and 318 of both plate indexing means 300 will provide identicalmovement to both sides of plates 50. This will ensure that the entirerow of holders is accurately advanced to be in registration with theentire row of feeder tubes.

The plate indexing means 300 shown in FIG. 9 acts to incrementallyadvance the carrier plates in a precisely controlled manner. Oneimportant feature is that the apparatus of the invention alwaysmaintains the carrier plates under a positive control. This isaccomplished through the coordinated movement of the pins 312 and 322 inand out of engagement with the transverse rows of engagement bushings 53in plates 50. As shown in FIG. 8, there is a single row of engagementbushings 53 on each end. The pins 312 and 322 must therefore engage asingle row of bushings 53. In order for this to be accomplished, theengagement bars 310 and 320 must have complementary shapes and cooperatein such a manner in order to enable both sets of pins 312, 322 to bepositioned along a single longitudinal axis. Referring now to FIG. 10, aplan view of engagement bars 310 and 320 is shown. As can be seen, thebars 310 and 320 have a tongue and groove like fitting arrangement whichallows for each of the sets of pins 312 and 322 to lie along a singlelongitudinal axis. In addition, the width of the "tongues" 332 is lessthan the width of the "grooves" 334 of engagement bars 310 and 320 whichallows for longitudinal movement of engagement bar 310 with respect toengagement bar 320. For the sake of simplicity, the relativelongitudinal movement of engagement bar 310 with respect to engagementbar 320 is shown in phantom only at the pin 312 located on the extremeleft hand side of the FIG. 10. Position 1, shown in phantom, is thelocation of the pins 312 prior to plate advancement. Position 2 is thelocation of the pins 312 subsequent after plate advancement. Engagementbar 320 does not move in the horizontal plane and therefore pins 322remain in the positions shown. For a full description of the relativemovement of pins 312 and 322, reference to FIG. 11 will be made.

Referring now to FIGS. 11(a)-(e) there is illustrated the sequentialoperation of the plate indexing means 300 for incrementally advancingthe plates 50. FIG. 11(a) shows an engagement pin 312 in position 1 inwhich the pin is engaged in a plate 50, while at the same timeengagement pin 322 is in position 1' out of engagement with a plate 50.Rotation of cams 316 and 326 90° advances the plates 50 thepredetermined distance equal to the center-line to center-line distancebetween each of the transverse rows of product holders in plates 50. Asshown in FIG. 11(b), pin 312 is advanced in the direction of productflow to position 2 causing each plates 50 to be advanced thepredetermined distance. As shown in FIG. 11(b), pin 322 remains inposition 1', out of engagement with plates 50. As explained above, thefirst 90° movement of cam 326 does not result in cam 326 contacting camfollower 324 so that no movement will occur to engagement bar 320. Asshown in FIG. 11(c), upon a second 90° rotation of cams 316 and 326, pin312 is moved out of engagement with plates 50 to position 3. The second90° movement of cam 326 causes movement of engagement bar 320 whichmoves pin 322 downward to position 2' engaging plates 50. Next, as shownin FIG. 11(d) the third 90° rotation of cams 316 and 326 results in pins312 moving in the opposite direction of product flow to position 4.During this 90° rotation of cam 326, no movement is effected toengagement bar 320 and thus pins 322 remain in position 2' engaged withplates 50. As noted previously, a positioning bar is in contact with camfollower 324 and is connected to the frame assembly of the processingapparatus to prevent longitudinal movement of the engagement bar 320.Thus, by maintaining pins 322 in engagement with plates 50 during thetime when pins 312 are out of engagement with plates 50, assures thatthe plates 50 are always under positive control. As shown in FIG. 11(e),the fourth 90° rotation of cams 316 and 326 results in pin 312 movingdownward to position 1 re-engaging plate 50. The fourth 90° rotation ofcam 326 results in movement of engagement bar 320 upward moving pins 322back up to position 1' out of engagement with plates 50.

As noted above, the relative shape of cams 316, 326 and cam opening 318,328 provide the complementary movement of engagement bars 310 and 320.Referring back to FIG. 9, the first box cam 304 includes an eccentriccam 316 rotatable 360° in the cam follower housing 314, each 90° ofrotation, providing a predetermined. motion time period and apredetermined dwell time period for the engagement bar 310. In theillustrative embodiment shown in FIG. 9, each 90° of rotation of cam 316provides a motion period for approximately 72° of that rotation and adwell time for approximately 18° of that rotation to move engagement bar310 in each of the four directions. Likewise, cam 326 is an eccentriccam rotatable 360° that provides for each 180° of rotation apredetermined motion time period and a predetermined dwell time periodfor the engagement bar 320. In the illustrative embodiment shown in FIG.9, each 180° of rotation of cam 326 provides a motion time period forabout 72° of that rotation and a dwell time period for about 108° ofthat rotation to move engagement bar 320 in each of two directions.

Plate indexing means 300 as described above, provides preciseincremental advancement of the plates 50 through the feeder means toprovide accurate feeding and loading of tablets onto the carrier plates.High precision in the loading of the tablets onto the plates isnecessary to allow the system to accurately coat the product with thevarious coating arrangements as desired. Conventional drive componentsincluding motors, drive shafts and the like are required to provide therotation to cams 316 and 326, all of which are well known to thoseskilled in the art and hence there is no need to provide details ofthese elements.

Referring now to FIGS. 1 and 12, the feeder means 80 includes hopper 82and a plurality of feeder tubes 84. Feeder means 80 also preferablyincludes separation means 86 for eliminating broken tablets so that onlyfull sized tablets are introduced into the hopper 82. Feeder means 80further includes dispensing means 88 for orienting and depositing one ormore products onto the product carrier plates 50. The separation means86 includes a perforated plate 81, shown in FIG. 13, that is caused tovibrate by a vibrator means 83. A plastic tote or other container 85containing a supply of product to be coated is attached to a chute 87.As shown in FIG. 12, tablets 10 in tote 85 are allowed to feed into thechute 87 causing the product to travel into a angled chute 89. Thetablets 10 are transferred through chute 89 in essentially a singlelayer to perforated plate 81. The perforated plate 81 and chute 89 areattached to the vibrator 83 and are positioned at an angle wherebyvibrations cause the tablets to "walk" across the perforated plate andfall into chute 91. Perforated plate 81 is comprised of a series ofholes 93 which are sized just slightly smaller than the diameter of thetablets to be coated. As the product walks across the perforated plate,partial or broken tablets will fall through the holes 93 while fullsized tablets will pass completely across the plate and fall into chute91. A bin 95 is positioned below the perforated plate 81 to collect thebroken pieces.

Chute 91 transfers the full tablets 10 to hopper 82 of feeder means 80.Reciprocating drive means 90 causes hopper 82 to move in an up and downmotion resulting in tablets 10 entering feeder tubes 84. The dispensingmeans 88 orients and dispenses the tablets 10 onto the plate means 50.The dispensing means 88 fills a plate 50 one row at a time. In apreferred embodiment of the present invention, feeder tubes 84 contain alinearly disposed plurality of product 10 to be deposited. It will beunderstood that FIG. 12 is a side view, partially cross-sectioned,therefore only one "column" of product is visible. However, in apreferred embodiment, a column of product 10 is positioned over eachproduct holder across an empty row of plate 50. In the preferredembodiment shown in FIGS. 9 and 12, the dispensing means includes aparallel linkage 91. The parallel linkage 91 causes product 10 to be fedin a single row and correctly positioned over a row of open productholders 31. Product control stops 92, 93 are positioned to extendradially into and out of the feeder tube 84. Stop control bars 94 and 96are attached to each product control stop 92, 93. In turn, the controlbars 94, 96 are connected by parallel links 97, 98. As shown in FIG. 10,the parallel linkage 91 is connected to engagement bar 310 through atransfer motion means 99. In operation, as shown in FIGS. 9, 10 and 12,when engagement bar 310 moves in a direction opposite to that of productflow shown by the arrow, the motion transferred via the links 97 and 98causes stop control bar 92 to come in contact with a tablet 10 holdingthat tablet in place preventing all tablets above that tablet to fallany further through the tube 84. At the same time, stop control bar 93is withdrawn from the tube allowing a single product to fall through thetube for placement onto the carrier plate 50. Upon the motion ofengagement bar 310 in the direction of product flow, motion will betransferred via links 97 and 98 to stop control bars 92 and 93 to causecontrol bar 93 to be reinserted into the feeder tube 84 and to releasestop control bar 92 from the tubes in order to allow products 10 to dropto a position shown in FIGS. 9 and 12. It is during movement ofengagement bar 310 in the direction of product flow that the tablet 10previously released by linkage 91 is oriented and dispensed onto aproduct holder 30.

A more detailed view of the actual orienting and dispensing of product10 onto the product holders is shown in FIGS. 14a and 14b. The means fordepositing and orienting a tablet 10 onto an open product holder 30 inthe illustrative embodiment of FIGS. 14a and 14b is a passive "knockover" mechanism. As shown, one side of the feeder tube, the sidedownstream of product flow, is provided with an opening 71. Theremaining portion of the feeder tubes 84 extend to a position nearlytouching the top of product holders 30 as shown at 72. When engagmentbar 310 is moved in a direction opposite to that of product flow causinga tablet 10 to fall all the way to the bottom of feeder tube 84, theposition of the product carrier 50 is such that the tablet falls ontothe previously deposited tablet. The resulting position of the firstreleased tablet is shown in FIG. 14a. Preferably, the product carrierplate 50 is positioned in relation to the feeder tubes 84 slightly offcenter so that the falling tablet 10 falls on a surface of thepreviously deposited tablet between the center of the tablet and the endof the tablet. This arrangement is preferred as compared to allowing thetablets 10 to fall directly onto an open product holder as it has beenfound that severe bouncing occurs when tablets fall directly onto theholders sometimes causing disorientation or damage to the tablets. Byhaving the tablet fall onto another tablet, the bouncing is reduced. Asthe engagement bar moves in the direction of product flow, the top halfof tablet 10, engages the bottom edge of the opening 71 and the lowerhalf of the tablet 10 is caused to rotate through the opening, therebyorienting the tablet with its greater diameter horizontally positionedand causing the tablet to land in that orientation onto the next openproduct holder as shown in FIG. 14b.

In a preferred embodiment of the present invention, the feeder means 80is also provided with a tablet setting means 400 downstream of thefeeder tubes in the direction of the product flow for properly seatingthe tablets in individual product holders after being dispensed from thefeeder tubes. The product setting means 400 can be seen in FIGS. 9 and10 and is shown in a detailed cross-sectional view in FIG. 15. Settingmeans 400 includes a setting head 402 connected to a reciprocating armmeans 404 for moving the setting head from a first position out ofcontact with tablets 10 to a second position shown in phantom in FIG. 15in which the head 402 contacts tablet 10. The head includes an opening406 shaped to be complementary to the shape of the product being set. Anactuating means is provided to control the reciprocating motion of thesetting means. In the embodiment shown in FIG. 15, the setting means 404is connected to engagement bar 320 which reciprocates up and down toselectively engage pins 322. In this embodiment, the setting means 400is moved into a position to contact the tablets each time the engagementbar is caused to move into the position where pins 322 are engaged inthe product holders 31. As shown in FIGS. 10 and 15, a row of settingmeans 400 is provided so that a row of products may be seated at a time.

In an alternative embodiment of the present invention as shown in FIG.16, the dispensing means is comprised of a transfer means for capturingproducts from the feeder tubes and disposing the product in the holdingfixtures or carrier plate means. In this embodiment, the dispensingmeans comprises a vacuum means 500 which includes a vacuum chamber 502connected to a vacuum source for delivering a vacuum to a plurality ofpick-up heads 504. An actuating means 506 is provided for positioningthe vacuum pick-up heads from a first position shown at 508 forcapturing products in the feeder tubes and for positioning the capturedproduct at a second position shown at 510 for releasing the product ontothe holding means. In this embodiment, the feeder tube guide meansincludes a seat 512 which acts as a capture seat means for retaining asingle product to be transferred. A parallel linkage 514 may optionallybe provided with a product control stop 516 which urges against a tabletimmediately above the tablet located in the capture seat 512. Thelinkage 514 results in the elimination of any force from the column oftablets on the tablet being captured that may interfere with the captureprocess. Alternatively, a pair of product stop bars similar to thatshown in FIG. 12 may be employed. In operation, the actuating means 506rotates the vacuum heads to the first position 508 and an extensionmeans 516 extends the vacuum chamber 502 and the vacuum heads 504 sothat the heads contact the tablets in the capture seat. The vacuum isactuated causing the tablets to be held by the vacuum heads 504. Theheads 504 are then retracted removing the tablets from the seat. Theretracted heads 504 with the captured tablets are then rotated to thesecond position where the heads 504 are again extended causing thetablets to be positioned on an empty row of product holders 31. Thevacuum is released and the vacuum heads 504 retracted resulting in thetablet being deposited on the product holders.

As shown in FIG. 17, the product pick-up means 504 is comprised of anouter pick-up shell 522 having tips 524 shaped complementary to theproduct being captured and deposited. A vacuum tube 526 is positionedwithin shell 522 and may itself be extended and retracted within theshell for increasing or decreasing the vacuum force applied to theproduct.

As shown in FIG. 17, a product setting means 520 may also be providedwith the vacuum feeder means 500. The setting means 520 is attached tothe vacuum chamber 502 and is rotated throughout the various positionsand is extended and retracted at the same time the vacuum pick-up heads504 are extended and retracted. Thus, when the vacuum heads 504 areextended to deposit a tablet onto a tablet holder the setting head 520is extended to properly seat the tablets in one or more rows downstreamof the tablets being deposited.

Although certain embodiments of the methods and apparatus of the presentinvention have been described above with particularity, these examplesare for purposes of illustration and are not limiting. Numerousvariations and adaptations of the principles of the present inventionwill immediately present themselves to those of ordinary skill.Accordingly, reference should be made to the appended claims toascertain the scope of the present invention.

What is claimed is:
 1. A feeder device for inserting a plurality of aproduct into a holding fixture during processing comprising:(a) hoppermeans for containing a plurality of said products; (b) feeder tube guidemeans connected to said hopper means for retaining and orienting saidproduct for transfer to said holding fixture; (c) transfer means forcapturing said product from said feeder tube guide means and disposingsaid product in said holding fixture, said transfer means comprising:(i)vacuum source means; (ii) one or more vacuum pick-up heads connected tosaid vacuum source means; and (iii) actuator means for positioning saidone or more vacuum pick-up means to capture and remove one or moreproducts from said feeder tube guide means and for releasing anddisposing said captured products into said holding fixture; and (d)product setting means for properly seating said product disposed inindividual product holders in said holding fixture.
 2. The device ofclaim 1 wherein said feeder tube guide means comprises one or morefeeder tubes which retain a plurality of products in a longitudinallyaligned orientation, and one or more product capture seat means whichretain a single product to be transferred.
 3. The device of claim 2wherein said feeder tube guide means further comprises parallel linkagemeans connected to one or more product stop bars for controlling thepositioning of a single product into said capture seat means.
 4. Thedevice of claim 3 wherein said feeder tube guide means includes a pairof product stop bars for each feeder tube.
 5. A feeder device forinserting a plurality of a product into a holding fixture duringprocessing comprising:(a) hopper means for containing a plurality ofsaid products; (b) feeder tube guide means connected to said hoppermeans for retaining and orienting said product for transfer to saidholding fixture; (c) transfer means for capturing said product from saidfeeder tube guide means and disposing said product in said holdingfixture, said transfer means comprising:(i) vacuum source means; (ii)one or more vacuum pick-up heads connected to said vacuum source means;(iii) product setting means for properly seating said product disposedin said holding fixture; and (iv) actuator means for positioning saidone or more vacuum pick-up means to capture and remove one or moreproducts from said feeder tube guide means for releasing and disposingsaid captured products into said holding fixture and for advancing andretracting said product setting means.
 6. The device of claim 5 whereinsaid feeder tube guide means comprises one or more feeder tubes whichretain a plurality of products in a longitudinally aligned orientation,and one or more product capture seat means which retain a single productto be transferred.
 7. The device of claim 6 where said holding fixturecomprises a one or more transverse rows of individual product holdersand a plate adapted to retain said individual product holders.
 8. Thedevice of claim 7 wherein said actuator means includes means forrotating said vacuum pick-up heads and said product setting meansbetween a first position wherein said pick-up heads are aligned withsaid product capture seat means and a second position wherein saidpick-up heads are aligned with a row of empty individual product holdersand wherein said product setting means are aligned with a row ofindividual product holders containing products therein.